A High-Density Ternary Barcode Detection System with a Dual-Bias Differential Method

Abstract

<span style="font-size:10.0pt;font-family:"">A dual-bias differential method is presented for increasing the detection range of a ternary barcode detection system. The system is provided with a second differential delay circuit with bias control to process optimally gray signals by lowering their averaged level using a clamping circuit. This is added to the primary conventional differential delay circuit without bias control and a comparator to process optimally black signals based on the envelope-differential fixed-period delay (EDFPD) detection technique. This method enables the system to detect over a longer range at high speeds while being capable of handling a large amount of information. The estimate results of gray and white code widths against the clamp bias made through the dynamic operation simulation of a differential circuit using SPICE were nearly consistent with the experimental results. Thereby we can conclude that</span><span style="font-size:10.0pt;font-family:""> the</span><span style="font-size:10.0pt;font-family:""> dynamic simulation is effective for estimation of </span><span style="font-size:10.0pt;font-family:"">an </span><span style="font-size:10.0pt;font-family:"">optimum clamp bias voltage. It was confirmed that the detection range of the system with a clamp bias voltage of </span><span style="font-size:10.0pt;font-family:"">?</span><span style="font-size:10.0pt;font-family:"">0.4 V for a minimum bar width W = 0.25 mm was 1.4 times that of the conventional EDFPD detection technique. In addition, the system operated at a maximum scanning speed of 7.7 times that of conventional CCD cameras under the practical detection range. The system with clamp bias control is expected to enable the real-time identification of goods on production lines and in automated warehouses.</span

A High-Resolution Laser Beam Collimator System with a High-NA lens for a High-Density Ternary Barcode Detection System

“…The scanning distance indicating the distance between the laser head and the surface of the barcode was nearly 15 cm on average. In this system, the detection range was controlled by adjusting the average level of gray signals using a clamp bias voltage in the clamping circuit [11]. It was expected that the average level of the gray signals changed depending on barcode pattern density and gray bar concentration.…”

“…The authors have developed ternary barcode detection systems (BCDSs) using laser diode Hiroo Wakaumi; A High-Resolution Laser Beam Collimator System with a High-NA Lens for a High-Density Ternary Barcode Detection System, Transactions on Networks and Communications, Volume 2 No 3 Aug (2014); pp: 29-37 (LD) scanning to resolve the above problems of low-speed scanning, focus adjustment and auxiliary lighting requirements [3][4][5]. In particular, the ternary BCDS using the dual-bias differential method could detect a 0.25 mm wide ternary barcode within a 7.4 cm detection range.…”

“…In particular, the ternary BCDS using the dual-bias differential method could detect a 0.25 mm wide ternary barcode within a 7.4 cm detection range. This performance has also been achieved with long detection distances of around 35 cm [5]. However, the detection of a minimum 0.2 mm wide ternary barcode equivalent to conventional binary barcodes has not yet been achieved.…”